Acording to the haynes book its 3.0 to 3.5 bar. not sure if it goes higher with the rising rate dunno..
The plan was to use it to try and lean out my mixture slightly and stop my car running mega rich at WOT.
The problem is i used a cheep ebay item that as ric said looks pritty but i have found out isn't very accurate. it might be a case that i got a dodgy one or i might just be too fussy.
I dont like messing around with fuel pipes too much as it can get a bit dodgy and from what i can tell the regulator was drawing in air someware so for now its off.
But the idea is still there and it might be something i consider soon but with a regulator of better quality and some proper braided fuel lines.
Bit of a shame that didn't go to plan but you dont know till you've tryed it :wink: